The present invention relates to a data recording/reproducing apparatus using a DVD (Digital Versatile Disk)-RAM and the like as a record medium, a data recording/reproducing method applied to the apparatus, and a computer program product used in a data processing apparatus. More particularly, the invention relates to a data recording/reproducing apparatus using a single record medium to handle audio/visual data such as DVD video and normal digital data used in a computer.
This application is based on Japanese Patent Applications No. 9-312344 filed on Nov. 13, 1997 and No. 9-329207 filed on Nov. 28, 1997, the contents of which are incorporated herein by reference.
In recent years, with progress of computer and multimedia, various multimedia-capable computer systems have been developed. Function for reproducing animation or sound data in addition to function for reproducing text data or graphic data is provided with such computer.
With such progress in multimedia of the computer, a DVD has lately drawn attention as a new record media taking the place of CD-ROM. One side of a single DVD-ROM media can store data of about 4.7 G bites which is about seven times volume of the current CD-ROM, and both sides of the DVD-ROM media can store data of about 9.4 G bites. By using the DVD-ROM media, it is possible to reproduce animation such as movie including a great amount of picture information on a computer at high quality.
On the other hand, development of a DVD-RAM media which can read out and write in data has also been developed recently. Since the DVD-RAM media is a media having a large volume and capable of being written, the DVD-RAM media is not only used for recording the animation data, but is also greatly expected as a secondary storing device of a computer. Further, the DVD-RAM media has drawn attention as a new record media taking the place of a video cassette in public equipment such as a video camera or video tape player.
Therefore, the DVD-RAM can handle both audio visual data (which is referred to as AV data hereinafter) which regards actual time property as most important, and digital data (which is referred to as D data hereinafter) which regards accuracy as most important such as file data used in the computer.
However, when there is a defective sector during recording into the DVD-RAM media, handling of the defective sector differs between AV data and D data. That is, in the case of AV data which regards actual time property as most important, it is preferable to keep recording even if the fact that data can not be recorded accurately in such a defective sector is ignored. On the other hand, in the case of D data, it is important to rewrite the D data in an alternative sector while regarding the accuracy as most important.
In general, an apparatus for recording/reproducing D data carries out, in recording processing of data, the verifying processing for checking whether the data has been correctly recorded after recording. Further, in reproducing processing of data, retry processing is carried out when a defect is generated. Since the D data is program data or file data made by various kinds of application soft, if a defect is generated, the entire program may not be executed. Therefore, the verifying processing and the retry processing which is performed when a defect is generated are necessary and indispensable since reliability is regarded as most important.
Whereas, the AV data comprises image data or sound data, and it is important that the data is recorded and reproduced without interruption. Even if a defect is generated when the data is recorded or reproduced, this does not make it impossible to reproduce the AV data although a noise is generated in a portion of the picture. Therefore, AV data does not necessarily require the verifying processing or the retry processing.
As described above, a degree of necessity of the verifying processing or the retry processing differs depending upon the kind of data. However, conventionally, the verifying processing is carried out when data is recorded, and the retry processing is carried out when data is produced irrespective of kinds of data. Therefore, regarding a method for recording and reproducing D data, when image data having a great amount of data is recorded, extra time for verifying processing is required. Further, when the image data is reproduced, if the retry processing is carried out, the image which is in reproducing is interrupted for a time during the retrying.
A first object of the present invention is to provide a data recording/reproducing apparatus which determines the kind of data and can execute the recording/reproducing processing in a suitable manner to the kind of data.
A second object of the invention is to provide a data recording/reproducing method applied to the data recording/reproducing apparatus.
A third object of the invention is to provide a computer program produce used in a data processing apparatus.
The above object is achieved by the following data recording and reproducing apparatus. That is, the data recording and reproducing apparatus executes recording and reproducing processing of a record medium in which at least two kinds of data having different data types can be stored. The data recording and reproducing apparatus reads out data from the record medium, detects a digital watermark from the data read out, and determines the kind of data depending upon whether the digital watermark is detected. The data recording and reproducing apparatus determines whether a defect is exists in the read out data, determines whether the retry processing should be carried out for the detected defect in accordance with the determined kind of data, and carries out the retry processing in accordance with a determination result.
In this data recording and reproducing apparatus, when the reading-out processing of two kinds of data or more having different data types is carried out, the kind of data is determined in accordance with whether the digital watermark exists in data, and the retry processing is carried out when a defect is generated in accordance with the kind of data. Therefore, in the case of data whose reading-out continuity is more important than reliability, the retry processing is omitted, and the reading-out processing time can be shortened.
Further, the data recording and reproducing apparatus of the present invention obtains data to be written, detects a digital watermark from the obtained data, determines the kind of data depending upon whether the digital watermark is detected, and writes the obtained data to the record medium. It is determined whether the verifying processing should be executed depending on the determined kind of data, and the verifying processing is executed in accordance with a determination result.
In this data recording and reproducing apparatus, when the reading-out processing of two kinds of data or more having different data types is carried out, the kind of data is determined in accordance with whether the digital watermark exists in data, and the verifying processing is carried out in accordance with the kind of data. Therefore, in the case of data whose recording continuity is more important than reliability, the verifying processing is omitted, and the writing processing time can be shortened.
Further, when a defect is generated in a sector for writing data in the storing area of the record medium and data to be written is determined that the verifying processing should not be executed, the data recording and reproducing apparatus of the invention may skip such a sector where the defect is generated and write the data in the following sector, or may write the data in the sector where the defect is generated.
In this data recording and reproducing apparatus, even if an OS or a file system detects a defect during the writing processing for example, the recording is continued without being interrupted by keeping writing sequentially while skipping the defective sector in accordance with the kind of data, or by keeping writing sequentially irrespective of whether there is a defective sector. In this case, there is a possibility that information in a portion in which a writing is carried out in a defective sector may be lost and may not be normally reproduced later. However, in the case of audio/visual data, if that portion is converted into reproduction time, the time for lost information is extremely short time, and if a known adjusting processing is carried out for that portion to lower the remarkability of the defect, it is possible to lower a degree of the problem to a satisfactory level as long as a man sees and listens to with his eyes and ears.
Further, the data recording/reproducing apparatus of the present invention reads out data from a record medium, and when a defect is detected during the reading-out processing of data, stores the position of the defective sector, and carries out the retry processing for the stored defect position after the reading-out processing of data is completed. The digital watermark may be detected from the data read out, the kind of data may be determined depending upon whether the digital watermark is detected, and it may be determined whether the retry processing for the stored defect position should be executed in accordance with the determined kind of data.
In this data recording and reproducing apparatus, when a defect is detected during the reading-out processing of data, the defect position is stored, and the reading-out processing of data through a specified area, thereby making it possible to reliably check whether a digital watermark exists in the data. Further, by executing the retry processing for the defect position in accordance with the kind of data after the data is read out, it is possible to avoid interruption of reading-out of data whenever a defect is detected, and to shorten the entire processing time.
The second object is achieved by the following data recording and reproducing method applied to a data recording and reproducing apparatus. That is, the data recording and reproducing method of the present invention is applied to a data processing apparatus which reads out a series of data in which a digital watermark is embedded. According to this data reading-out method, even if a defective sector is detected when the series of data is being read out, the retry processing for the defective sector is not executed, and the reading-out of the series of data is completed, the digital watermark is detected from the reading-out series of data, and the kind of data is determined depending upon whether the digital watermark is detected.
According to the data reading-out method, it is determined whether the retry processing for the defect should be executed depending upon the determined kind of data, and when it is determined that the retry processing should not be executed, reading-out of data next to the series of data is continued, and when it is determined that the retry processing should be executed, the retry processing for the detected defective sector is executed.
The third object is achieved by the following computer program product used for the data processing apparatus. That is, the computer program product of the present invention is used for a data processing apparatus which reads and writes at least two kinds of data having different data types, and causes the data processing apparatus to detect a digital watermark from data and to determine the kind of data depending upon whether the digital watermark is detected.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.